title: Patient dependence and longitudinal changes in costs of care in Alzheimer's disease.
abstract: OBJECTIVE
  To examine the incremental effect of patients' dependence on others, on cost of medical and nonmedical care, and on informal caregiving hours over time.
  
  
  METHODS
  Data are obtained from 172 patients from the Predictors Study, a large, multicenter cohort of patients with probable Alzheimer disease (AD) followed annually for 4 years in 3 University-based AD centers in the USA. Enrollment required a modified Mini-Mental State Examination score >or=30. We examined the effects of patient dependence (measured by the Dependence Scale, DS) and function (measured by the Blessed Dementia Rating Scale, BDRS) on medical care cost, nonmedical care cost, and informal caregiving time using random effects regression models.
  
  
  RESULTS
  A one-point increase in DS score was associated with a 5.7% increase in medical cost, a 10.5% increase in nonmedical cost, and a 4.1% increase in caregiving time. A one-point increase in BDRS score was associated with a 7.6% increase in medical cost, a 3.9% increase in nonmedical cost and an 8.7% increase in caregiving time.
  
  
  CONCLUSIONS
  Both functional impairment and patient dependence were associated with higher costs of care and caregiving time. Measures of functional impairment and patient dependence provide unique and incremental information on the overall impact of AD on patients and their caregivers.
authors.affiliation: Geriatric Research, Education, and Clinical Center (GRECC), James J. Peters VA Medical Center, Bronx, NY, NY 10468, USA. carolyn.zhu@mssm.edu
authors.forename: Carolyn W
authors.initials: CW
authors.lastname: Zhu
authors.forename: Christopher
authors.initials: C
authors.lastname: Leibman
authors.forename: Trent
authors.initials: T
authors.lastname: McLaughlin
authors.forename: Arthur S
authors.initials: AS
authors.lastname: Zbrozek
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Scarmeas
authors.forename: Marilyn
authors.initials: M
authors.lastname: Albert
authors.forename: Jason
authors.initials: J
authors.lastname: Brandt
authors.forename: Deborah
authors.initials: D
authors.lastname: Blacker
authors.forename: Mary
authors.initials: M
authors.lastname: Sano
authors.forename: Yaakov
authors.initials: Y
authors.lastname: Stern
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000544:Alzheimer Disease / Q000191:economics* / Q000628:therapy*; D017028:Caregivers / Q000523:psychology / Q000706:statistics & numerical data; D015331:Cohort Studies; D003365:Costs and Cost Analysis; D003430:Cross-Sectional Studies; D003704:Dementia / Q000523:psychology; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009483:Neuropsychological Tests; D011569:Psychiatric Status Rating Scales; D012959:Socioeconomic Factors; D014481:United States